A circular current carrying coil has a radius R.The distance from the centre of the coil axis is the coil, where the magnetic induction is 1/8th of its valus at the centre of coil is

Explanation

Field at centre `B_(1)=mu_(0)I/2R,`Field at distance x `B_(2)=mu_(0)IR^(2)/2(R^(2)+x^(2))^(3/2)`
Given `B_(2)=B_(1)//8` `mu_(0)IR^(2)/(2R^(2)+x^(2))^(3/2)=1/8(mu_(0)I/2R)`,Solving we get `x=sqrt(3)R`